The present invention relates to a travel sensor for measuring mechanical quantities of motion, particularly, for determining brake pedal position of a brake pedal of an automotive vehicle.
Travel sensors of this type are utilized in current practice for various reasons and for different applications. For example, brake systems can be monitored by means of such travel sensors. For measuring the pedal travel in such systems, the advance motion of the booster pistons and master brake cylinder pistons or the like advantageously can be utilized for obtaining control signals and regulating signals for anti-lock control or traction slip control.
Known travel sensors for measuring the translatory or rotational movement, for example, the brake pedal movement of an automotive vehicle, utilize the principle of voltage division, according to which the current flow through an electrical resistance is tapped by way of a displaceable collector ring. This provides a partial voltage. The transmission of kinematics from the brake pedal to the travel sensor thereby influencing the respective test voltage is performed by relatively large mechanical transmission elements as well as transmission distances which considerably increase the overall length of the sensor. For example, this may include the distance for transmitting the tappet stroke to the measurement input, and hence impair the space requirement. Considerable expenditure is required in order to obtain reliable construction elements which are safe in function particularly for frequent operation. Also, the slide contact is exposed to relatively great wear.
Therefore, it is an object of the present invention to devise a sturdy, small-sized and especially short travel sensor which can be manufactured at low cost and effort and hence is appropriate for use on medium-priced and lower-priced automotive vehicles. The sensor should accommodate relatively large travel variations with great reliability and with the necessary accuracy. Accordingly, it is a particular object to achieve in a simple and technically progressive manner a sensor of the type initially referred to.